Echinacea purpurea 
Echinacea sp. plant has been used as a natural medicine for many years up to the present. This genus corresponds to native North American plants which characterized by its red or purple flowers, however only three of them such as Echinacea angustifolia, Echinacea pallida and Echinacea purpurea are used for medical purposes.
In the field of medicinal plants, Echinacea purpurea is one of the most investigated plants, due to its properties as stimulant of immune system (Bauer and Wagner 1991). The therapeutic activity of the E. purpurea has been attributed to its content of caffeic acid, chlorogenic acid, echinacoside and lipophilic derivative compounds alkylamides.
Most of alkylamides are reported to act as potent inhibitors of cycloxygenase. Inhibitory properties of arachidonic acid on the metabolism are in accordance with the traditional use of the plant in the therapy of inflammatory diseases.
Among constituents of Echinacea purpurea has been described phenylpropanoids such as caffeic acid, derivatives as echinacoside, caftaric acid, chlorogenic acid (Bauer 1991). Additionally there are other constituents as flavonoids, including rutin whose highest concentration in leaves is in E. purpurea; the quercetin at 0.48% and with a minimum amount in E. angustifolia. 
Further components are terpenoid compounds including borneol and some others which are unique to each species. Lipidic compounds, polyacetylenes have been partially elucidated and reported with a content of 2% in the roots and alkylamides which are mostly occurring in E. purpurea which is one of the differences with respect to other two Echinaceas sp species. There is a multitude of Echinaceas sp. developed for decorative purposes.
Other constituents found in Echinaceas sp. are reduced sugars, phytosterols and ascorbic acid in a concentration of 0.214%.
Echinacea purpurea is generally used to reduce inflammatory processes for example in arthritis and promotes the T-cells formation in inflammatory conditions of the skin in external use. In Germany, where the use of this plant was generalized, the plant was used for helping the organisms to resist flu infections and throat conditions in concomitance to the flu (Bradley 1992).
Myrciaria dubia 
Some research evidences report that alkylamides have an immuno-stimulatory effect (Goel Y et. al. Alkylamides of Echinacea purpurea Stimulate alveolar macrophage function in normal rats. International Inmunopharmacology 2:381-387-2002). Myrciaria dubia, also known as Araza of water and camu camu is a fruit plant of bushy type native of the Amazon rainforest, existing in some Peruvian affluents of Amazon River and some affluent of provinces of Napo and Sucumbios in Ecuador. This plant grows wild along river banks of Ucayali, Pacaya and Napo rivers, and it is a much ramified shrub, under 3 m of height in size generally, with globose fruits with colouring varying from pink to dark red violet, containing 1 to 4 seeds covered by a mesh of white fibers, its fruits are characterized by their high vitamin C content, containing 2800 mg per 100 g of pulp (the orange contains an average of 60 mg per 100 g, depending of the variety) (Collazos C. White H. Composition of Peruvian foods).
This plant is considered the greatest Vitamin C natural source overcoming the Acerola, and its extract has applications as an antioxidant and recently in cosmetics as a whitening agent for spotted skins (Japanese Patent JP-A 9-221429).
Among the metabolites found in this Amazonian plant was found ellagic acid which is employed in the treatment of tumoral pathologies, due to its properties of generating apoptosis. Also are alpha pinene and d-limonene. This plant also has iron, niacin, riboflavin, calcium, and amino acids such as leucine, proline and serine.
The invention describes a composition comprising dry extracts of Echinacea purpurea and Myrciaria dubia having a synergistic effect for improving the immune response to infectious diseases including flu infections.
Echinacea purpurea has been used for years as a drug up to the present. As a medicine, have been used several extraction methods, including organic solvents and isolation by column chromatography. Some of its components such as isobutylamides have shown immuno-stimulatory activity, but when it is combined with metabolites of Myrciaria dubia including ellagic acid, the antioxidant activity is potentiated, i.e. unstable molecules of free radicals lose their destabilizing action and contribute to improve the pathologic process, especially when the human is under the action of virus and hostile pathogenic bacteria.
The flu, influenza or common cold caused by virus causes a loss of 10 billion dollar per year in the U.S.A despite all the support to the patient, such as analgesics, vaccines and drugs suggested for these cases.
The working time lost by this disease is an average of 3 days (Keech et. al The impact of influenza and influenza like illness on productivity and healthcare resources utilization on a working population. Occup Med (London) 1998, 48 85-90).
Influenza, flu, or common cold is a viral process potentially dangerous in children and elderlies, and to whom with pre-existing health problem. Every year, 500 million people are infected and about 5 million of these in a severe form, and reported 500 thousand of deaths (World Health Organization fact sheet-211, March 2003).
Usually, influenza has been treated with OTC products including analgesics, antihistamines, expectorants, decongestants, vaccines, which involve egg proteins and in some cases produce episodes of allergies; old generation antiviral as M2 channel blockers and subsequently with neuraminidase inhibitors. This whole arsenal seeks to reduce the severity of symptoms and shorten the period of illness. Side effects are known for everybody.
Flu complications lead to the patient being affected by pneumonia or bronchitis, so the recovery time can be extended to two months. Flu is an acute respiratory disease caused by flu virus, mainly affecting the respiratory tract (nose, throat and bronchi), the infection usually lasts a week and is mainly characterized by sudden appearance of high fever, myalgia, headache, weakness, cough, sore throat and rhinitis, most patients recover in 1 to 2 weeks without requiring medical treatment. The flu spreads rapidly around the world.
The influenza viruses are currently classified in two types A and B, and influenza virus A has shown an ability to cause pandemics. Pandemic viruses are caused by antigenic transfers, which are characterized by higher genetic changes in the hemagglutinin subtype, with or without change in neuraminidase.
In the XX century have been documented three major pandemics: Spanish flu 1918 by the influenza virus A (H1N1) with 20 million of dead, the Asian flu type A (H2N2), and the Hong Kong by the influenza type A (H3N2) in 1968. Currently these viruses are in circulation and it is expected to occur a new pandemic arising from the strain of virus that causes avian flu (H5N1).
Should a pandemic occur must meet the following conditions:    1. To occur the emergence of a flu strain for which a lot of people are not protected.    2. Transmission of the new virus from person to person quickly.    3. To cause disease in humans in massive scale.
Avian flu meets all these requirements. Flu with such characteristics can affect 20% of the world population. It has been reported cases of human infected in Asia.
In common flu, the incubation ranges from 1 to 4 days. The person who has flu is contagious from the day before the beginning of symptoms until seven days later, but in immunocompromised persons this period is greater.
The risk for a human to contracting the disease during the circulation of the virus depends of the following factors:    1. Virulence of the circulating strain.    2. Natural level of immunity, human general health and previous exposure to influenza virus or vaccination.    3. Basal or nutritional state.    4. Habitability; increased risk of transmission in closed spaces.    5. Age; common in people over 60 years and preschoolers.
The management of flu infection has as its object to help the immune system to eliminate the virus in a few days, usually bed rest and drink a lot of liquids are recommended. Vitamin C has been associated with improvement evolution of respiratory infections. The ethno-medicine uses garlic, lemon juice, thyme, eucalyptus or peppermint teas, which has antiviral action in vitro and the Echinacea sp for reducing the duration of flu. Further, homeopathy prescribes the Oscillococcinum which reduces the flu in a few days. General hygiene measures are indicated to avoid contagiousness.
Fever is an alarm mechanism that physiologically activates monocytes and various immune mediators but the use of antipyretics on flu in adults is controversial. As antivirals, amantadine and zanamivir are used for help to reduce the duration of flu symptoms in 1 or 2 days, their benefit is marginal. Zanamivir inhibits neuraminidase enzyme which blocks viral replication, another inhibitor used is oseltamivir.
Vaccination is a basic measure to prevent the flu and it is recommended for people over 60 years of age, or for whom which have high risk of complications as in the case of obstructive lung disease, chronic heart disease, chronic kidney disease or immunosuppression. In persons over 60 years of age non-hospitalized, vaccines reduce the morbidity in 60% and mortality in 70% mortality, and for hospitalized persons the effectiveness drops at 30-40%.
In patent literature of the previous art related to these plants individually, the Echinacea purpurea is mentioned in 152 patent documents.
Myrciaria dubia is mentioned in the following documents: US2006/0104927, JP 2005253307, JP 2004189698, JP 2001031558, JP 2000342162, JP 2000327525, JP 2000327553, JP 2000327552, JP 2000327550, JP 2000327549, JP 9215475, JP 11246336, JP 9221429, JP 9140341 and RU 2311190.
The state of the art is completely silent in relation to documents which include a combination of both extracts, namely, Echinacea purpurea and Myrciaria dubia. 
In the prior art there are published dissimilar anti-flu compositions, however they are unable to decrease certainly the time of pathology and only in somehow relieve the symptoms of viral processes, but not significantly shorten the duration of the process. Another drawback of existing anti-flu drugs is the coexistence of undesired side effects, with a high impact in many cases, avoiding or limiting their use in people with chronic concomitant diseases.